Bridge for pianos



April 8, 1930. w. SCHWECHTEN BRIDGE FOR PIANOS Filed Feb. 12, 1925 m u m r w Patented Apr. 8, 1930 UNITED STATES PATENT OFFICE BRIDGE r03 PIANOS Application filed February 12, 1923, Serial No. 618,728, and inGermany August 21, 1922.

My invention relates to improvements in pianos and similar musical instruments, and more particularly to the construction of the bridge, and the object of the improvements is to provide a bridge the volume of which is enlarged as compared to bridges of ordinary construction, while the contacting surface of the bridge on the sound-board is at least not increased and preferably is reduced, said contacting surface being preferably not much larger than is required in view of the strength of the sound board as agannst the strains exerted thereon by the bridge. I have found that by thus constructing the bridge the oscillating capacity of the sound-board is not affected by the bridge in a higher degree than in constructions now in use, and that the bridge takes part in a higher degree in the oscillations of the sound-board, whereby the 2 timbre of the tone of the instrument is materially improved. In my opinion this'result may be explained by the fact that in instruments such as are now in use the natural oscillations of the sound-board and the bridge are not in harmony with each other, so that the bridge interferes with the oscillation of the sound board, and that by increasing the volume or mass of the bridge a better harmony is insured which results in a better tone.

For the purpose of explaining the invention several examples embodying the same have been shown in the accompanying drawing, in which,

Figs. 1 to 7, are sectional views showing- 5 various embodiments of the invention,

Fig. 8, is a perspective View showing another modification, and

Fig. 9, is a sectional view showing a further modification.

In Fig. 1 the character 1 indicates the sound-board and the character 2 the bridge, the bottom face 3-4 of which is glued to the sound board, and which is provided with pins 5 for holding the strings 6 in position, as is known in the art. The size of the bottom face of the bridge represented by the characters 3-4 corresponds substantially to the usual dimension of the bridge, and it is preferably not much larger than is necessary in view of the pressure of the bridge on the sound board.

As distinguished from constructions now in use in which the cross-section of the bridgeis substantiallyin the form of a rectangle, or of even breadth throughout its height, my improved bridge is formed at both sides with enlargements or broad ribs 7 extending longitudinally of the bridge, so that the volume or the mass of the bridge is materially increased as compared to constructions now in use. I have found that thereby the timbre of the sound is materially improved. 1 I

In Fig. 2 I have shown a modification in which the bottom face of the bridge bearing on the sound-board is reduced by forming the bridge at its bottom part with a longitudinal groove 8, so that the bridge bears on the sound-board only with the surfaces represented in the said figure by the letters 3-3 and 4-4, the dimension 34 being substantially the same as the corresponding dimension of the bridge shown in Fig. 1. Other wise the form of the bridge is the same as that shownin Fig. l, and similar reference characters have been used'in both figures to indicatecorresponding parts, so that it is not necessary to repeat the description of such parts. I'have found that it is not necessary to provide enlargements at both sides of the bridge, and that a si'ngleenlargement provided at one side of the bridge will produce similar results. Constructions showing this modification have been shown in Figs. 3 and 4, Fig. 4 showing in addition a longitudinal groove 8v corresponding to the groove 8 described with reference to Fig. 2. {In both figures the enlargement of thebridgehas been indicated by the numeral 9. Asshown the cross-section of the rib 9 is larger than one of the ribs 7 This construction will be useful in such cases in which there is no room at one side of the bridge for the provision of a rib. Fig. 5 shows a modification in which the enlargement or enlargements are not in the form ofone or two ribs provided, at the side or sides ofthe bridge, but in the form of asubsidiarytor sectional bridge glued or other: wise secu'red'to the side of the sound-board opposite to the main part of the bridge. As shown inthe said figurethe main part. 10

I struction shown in the drawing,

of the bridge is similar as to form and dimension to the ordinary bridge now in use, and it has the strings 6 supported thereon and held in position by the pins 5. The sub sidiary bridge section 11 which is secured to the opposite side of the sound-board has a bearing surface making contact with the sound-board which is substantially equal to the bottom or hearing face of the main portion 10, and the body 11 is formed at both sides with ribs or flanges 12.

In Figs. 6 and 7 I have shown modifications in which the bridge consists of an enlarged main section and a subsidiary section secured to the opposite side of the sound board. In Fig. 6 the main section 13 and the subsidiary portion 15 are both provided at one side with an enlargement or rib 14 and 16 respectively, and in Fig. 7 the main section 17 is formed with two ribs 18 and 18' one at each side. The subsidiary section 19 consists of a piece of metal having flanges at both sides and secured to the main section by means of screws 20.

The modification shown in Fig. 8 is similar to the one described with reference to Fig. 5, but the main section 21 and the subsidiary section 23 are formed with longitudinal grooves 24 and 25 respectively. In addition the said sections are provided with transverse grooves 26 for reducing the surfaces of the foot portions 27 of the sections bearing on the sound-board to a minimum. The section 23 is provided with flanges 22.

Fig. 9 shows a main section 28 of the bridge in the form described with reference to Fig. 2 and combined with a subsidiary section 29 similar to the subsidiary section 23 illustrated in Fig. 8. The subsidiary section 29 may be made of wood or metal.

While in describing the invention reference has been made to a particular example embodying the same I wish it to be understood that my invention is not limited to the conand that various changes may be made in the general arrangement of the apparatus and the construction of its parts without departing from the invention.

I claim:

1. A device for a stringed musical instrument having a sound-board comprising a bridge having its mass substantially increased between the strings and the soundboard over that of a standard bridge to produce sounds of an improved timbre of tone, and strings bearing on said bridge.

2. 'A device for a stringed musical instrument having a bridge having its mass substantially increased over that of a standard bridge to produce sounds of an improved timbre of tone and bearing on said sound-board with a surface which is not increased as compared to the normal, and strings bearing on said sound-board comprising a 1 bridge and spaced equidistant from said sound-board.

3. A device for a stringed musical instrument having a sound-board comprising a bridge having an enlargement freely pro- Jecting at one side thereof, above and free from said sound-board, to produce sounds of an improved-timbre of tone, and strings bearing on said bridge.

4. A device for a stringed musical instrument having a sound-board comprising a bridge having enlargements at both sides in a plane substantially midway between the sound-board and the strings to increase the weight thereof to produce sounds of an improved timbre of tone, and strings bearing on said bridge.

5. A device for a stringed musical instrument having a soundboard comprising a bridge made in main and subsidiary sections provided at opposite sides of the soundboard, both sections being formed with cutout portions at the sides bearing on the sound-board, and the mass of each section being substantially greater than normal to produce sounds of an improved timbre of tone, and strings bearing on said bridge.

6. A device for a stringed musical instrument having a sound-board comprising a bridge having its mass substantially increased over that of a standard bridge to produce sounds of an improved timbre of tone and having a face bearing on said sound-board with a surface just large enough to resist the load of the bridge on the sound-board.

In testimony whereof I hereunto aflix my signature.

WILI-IELM SCHWECHTEN.

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